From 4678c00e9dd5f246ea1078912e9564b9e938400a Mon Sep 17 00:00:00 2001 From: Levin Du Date: Sat, 4 Aug 2018 15:31:02 +0800 Subject: clk: rockchip: Add pclk_rkpwm_pmu to PMU critical clocks in rk3399 [ Upstream commit 640332d1a089909df08bc9f3e42888a2019c66e2 ] PWM2 is commonly used to control voltage of PWM regulator of VDD_LOG in RK3399. On the Firefly-RK3399 board, PWM2 outputs 40 KHz square wave from power on and the VDD_LOG is about 0.9V. When the kernel boots normally into the system, the PWM2 keeps outputing PWM signal. But the kernel hangs randomly after "Starting kernel ..." line on that board. When it happens, PWM2 outputs high level which causes VDD_LOG drops to 0.4V below the normal operating voltage. By adding "pclk_rkpwm_pmu" to the rk3399_pmucru_critical_clocks array, PWM clock is ensured to be prepared at startup and the PWM2 output is normal. After repeated tests, the early boot hang is gone. This patch works on both Firefly-RK3399 and ROC-RK3399-PC boards. Signed-off-by: Levin Du Signed-off-by: Heiko Stuebner Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/clk/rockchip/clk-rk3399.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/clk/rockchip') diff --git a/drivers/clk/rockchip/clk-rk3399.c b/drivers/clk/rockchip/clk-rk3399.c index 05671c03efe2..410998800af5 100644 --- a/drivers/clk/rockchip/clk-rk3399.c +++ b/drivers/clk/rockchip/clk-rk3399.c @@ -1521,6 +1521,7 @@ static const char *const rk3399_pmucru_critical_clocks[] __initconst = { "pclk_pmu_src", "fclk_cm0s_src_pmu", "clk_timer_src_pmu", + "pclk_rkpwm_pmu", }; static void __init rk3399_clk_init(struct device_node *np) -- cgit v1.2.3